I am considering the construction of a "simple" phono preamp to connect my old Ariston RD40 turntable with MC cartridge to my pc to enable the transfer of some old lp recordings. Can anyone offer some guidance on suitable circuits solid state or tube. Martin
Are you sure it's an MC cartridge not MM?
I would avoid software RIAA correction as the dynamic range is poor.
I would avoid software RIAA correction as the dynamic range is poor.
The Hagerman Bugle: Hagerman Technology LLC: Bugle Opamp Moving Magnet Budget Phonostage DIY Kit is well regarded. I've built one, and it's what I am planning on using to do my LP to digital conversion.
Even these: Phonopreamps.com Home Page are pretty decent from what I have read..
Even these: Phonopreamps.com Home Page are pretty decent from what I have read..
Check out this thread..
http://www.diyaudio.com/forums/analogue-source/28223-ultrasimple-mm-mc-riaa-preamp-2-a.html
http://www.diyaudio.com/forums/analogue-source/28223-ultrasimple-mm-mc-riaa-preamp-2-a.html
There is an AES paper by the guy from Channel D that may have you rethinking that. I will be trying his solution soon in conjunction with an Edirol FA66
dave
Hi,
richie00boy is correct. Software equalizing costs on dynamic range.
Each Bit represents app. 6dB of dynamic range. The RIAA-curvature spans roughly a 40dB range between 20Hz and 20kHz, So one has to spare 7bits for the equing alone. Add to this a headroom of 1 to 2 bits to avoid clipping and you end up with at least 8 to 9 Bits of the ADC´s resolution. In case of a 20Bit ADC this means that just 11-12 bits are left free, representing a marginal dynamic range of just 66-72dB.
This dynamic range is only applicable in the case that the ADC is supplied with just the right voltage levels for it´s reference voltage and signal input voltage. Since most ADC´s reference voltage settle between 3.3V and 5V the phono-cartridge signal requires linear amplification, or the reference voltage needs to be lowered to match the cartridges output voltage. The latter costs resolution because of noise issues. The former would be the preferrably solution, but if You need amplification anyway, what´s the sense then in not to use hardware equing at the same and omitting with software equing alltogether?
IMHO using a fine phono-stage with linear output, driving an ADC with healthy levels of voltage is still the finest solution.
jauu
Calvin
richie00boy is correct. Software equalizing costs on dynamic range.
Each Bit represents app. 6dB of dynamic range. The RIAA-curvature spans roughly a 40dB range between 20Hz and 20kHz, So one has to spare 7bits for the equing alone. Add to this a headroom of 1 to 2 bits to avoid clipping and you end up with at least 8 to 9 Bits of the ADC´s resolution. In case of a 20Bit ADC this means that just 11-12 bits are left free, representing a marginal dynamic range of just 66-72dB.
This dynamic range is only applicable in the case that the ADC is supplied with just the right voltage levels for it´s reference voltage and signal input voltage. Since most ADC´s reference voltage settle between 3.3V and 5V the phono-cartridge signal requires linear amplification, or the reference voltage needs to be lowered to match the cartridges output voltage. The latter costs resolution because of noise issues. The former would be the preferrably solution, but if You need amplification anyway, what´s the sense then in not to use hardware equing at the same and omitting with software equing alltogether?
IMHO using a fine phono-stage with linear output, driving an ADC with healthy levels of voltage is still the finest solution.
jauu
Calvin
Read the paper, He does a MUCH more thorough analysis of the pluses & minuses. It is, IB, downloadable from his site,
CHANNEL D - Professional and Audiophile Quality Software for Vinyl, iTunes, and commercial applications
Here it is... the 2 papers at the bottom of the Pure Vinyl section.
dave
CHANNEL D - Professional and Audiophile Quality Software for Vinyl, iTunes, and commercial applications
Here it is... the 2 papers at the bottom of the Pure Vinyl section.
dave
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